Power-split angular gear

ABSTRACT

An angle drive having a housing ( 11 ) with a first axis (A 1 ) for bearing means and a second axis (A 2 ) for bearing means, which latter axis (A 2 ) intersects the first axis (A 1 ) at right angles, having an input shaft  16  which is supported in the housing, which carries an input ring gear ( 19 ) and is positioned on the first axis (A 1 ), having an output shaft ( 28 ) which is supported in the housing, which carries an output gearwheel ( 27 ) and is positioned on the second axis (A 2 ), having a counter ring gear  20  which is supported in the housing, which is positioned on the first axis (A 1 ) and which, with reference to the second axis (A 2 ) is arranged and designed symmetrically relative to the input ring gear ( 19 ), having at least one intermediate gearwheel which is supported in the housing, which is arranged on an axis (A 3 , A 4 )positioned radially relative to the first axis (A 1 ) and in one plane together with the second axis (A 2 ) and which is provided with the same type of toothing as the output gearwheel ( 27 ). The counter ring gear ( 20 ) is supported so as to be independently rotatable relative to the input ring gear ( 19 ). The input ring gear ( 19 ) and the counter ring gear ( 20 ), via their respective teeth, simultaneously engage the output gearwheel ( 27 ) and the at least one intermediate gearwheel.

BACKGROUND OF THE INVENTION

The invention relates to an angle drive having a housing with a firstaxis A₁ for bearing means and a second axis A₂ for bearing means, whichlatter axis A₂ intersects the first axis A₁ at right angles, having aninput shaft which is supported in the housing, which carries an inputring gear and is positioned on the first axis A₁, having an outputshaft, which carries an output gearwheel and is positioned on the secondaxis A₂. Angle drives can be used in many ways in motor vehicles, landmachinery and machines tools, just to mention a few applicationexamples. In the field of motor vehicle technology, they are required infour wheel drive vehicles with transversely built-in front engines. As arule, such vehicles are derived from basic models with a front wheeldrive only. In such cases, the angel drive directly follows adifferential drive of the front axle, with the input shaft of the angledrive being firmly coupled to the differential carrier of thedifferential drive. The input shaft of the angle drive is provided inthe form of a hollow shaft through which one of the sideshafts of thedifferential drive leads to the front axle drive.

The installation space of the angle drive to be accommodated in this waybetween the front axle differential and a drive-shaft behind orunderneath the combustion engine is naturally very limited. Because ofan ever increasing use of diesel engines with a high torque, thepreviously used angle drives reach their performance limit, i.e. inmaximum torque test runs, the required service life is no longerreached. Because of the limited installation space, the size of theangle drive cannot be increased, and it has to be taken into accountthat the transferable torque of angle drives is primarily determined bythe ring gear diameter which cannot be increased.

SUMMARY OF THE INVENTION

It is the object of the invention to provide an angle drive, especiallyfor said preferred application, which comprises a higher torque capacityin a given installation space, especially with a limited diameterdimension.

For this purpose, there is provided an angle drive with the followingcharacteristics:

having a counter ring gear which is supported in the housing, which ispositioned on the first axis A₁ and which, with reference to the secondaxis A₂, is arranged and designed symmetrically relative to the inputring gear (large gearwheels),

having at least one intermediate gearwheel which is supported in thehousing, which is arranged on an axis A₃, A₄ positioned radiallyrelative to the first axis A₁ and in one plane together with the secondaxis A₂ and which is provided with the same type of toothing as theoutput gearwheel (pinions), the counter ring gear is supported so as tobe independently rotatable relative to the input ring gear,

the input ring gear and the counter ring gear (large gearwheels), viatheir respective teeth, simultaneously engage the output gearwheel andthe at least one intermediate gearwheel (pinions).

In said angle drive, the above means achieve a power distribution which,because the output gearwheel is engaged twice, i.e. by the input ringgear on the one hand and by the counter ring gear on the other hand,leads to the tooth forces at the former being halved. The input ringgear and the counter ring gear which, substantially, are of identicaldesign, are subjected substantially to the same loads. Because theysimultaneously engage the output gearwheel and the at least oneintermediate gearwheel, their tooth forces are at least halved.

By halving or dividing into three the tooth forces with a given ringgear diameter, with an unchanged toothing shape and the same toothstrength, the transferable torque can ideally be doubled. In this way,by using high-torque diesel engines, the problems existing in connectionwith angle drives are solved completely. The invention allows a largering gear at the differential carrier to be replaced by smaller ringgears in the form of an input gearwheel and a counter gearwheel.

Independently of the preferred application mentioned here, an angledrive with power distribution of said type can also be used incombination with a rear axle differential. When the vehicle is drivingforward, the torque flow can take place from the shaft so far referredto as output shaft to the shaft so far referred to as input shaft. Thisalso applies to other applications.

According to a first preferred embodiment, a single intermediategearwheel is supported co-axially relative to the second axis A₂.According to a further embodiment it is proposed that several,especially two intermediate gearwheels, by means of their radial axesA₃, A₄, form identical pitch angles with the second axis A₂.

Furthermore, it is proposed that the input shaft is a hollow shaftthrough which a through-shaft is able to pass; that the input shaft issupported twice in the housing; that the input ring gear and the counterring gear on the input shaft are floatingly supported in the housing;that the counter ring gear is supported on the input shaft by means of aradial bearing; that the counter ring gear is axially supported on theinput shaft by means of an axial bearing; that the output shaft issupported once in the housing; and that at least one intermediategearwheel is rotatably supported on a fixed housing journal.Furthermore, it is possible that the input ring gear and the counterring gear are crown wheels and that the output gearwheel and the atleast one intermediate gearwheel are spur gears with straight toothingor helical toothing. The toothings can also be provided in the form ofspiral toothings or as helical toothings at the input ring gear and atthe counter ring gear and, accordingly, in the form of spiral orstraight or helical toothings at the output gearwheel and at theintermediate gearwheels. Further possibilities consist in that the inputshaft is axially floatingly supported in the housing and that there isarranged a plug-in sleeve in the journal end of the input shaft for thepurpose of being connected to an output shaft of a differential.

By supporting the input ring gear and the counter ring gear on the inputshaft, the housing is kept completely free from axial forces in thedirection of the first axis A₁. If the toothing is selected in the formof crown wheels or straight spur gears, the output shaft, too, is keptcompletely free from forces extending in the direction of the axis A₂.Because of being engaged twice, i.e. by the input ring gear and by thecounter ring gear, the output gearwheel is held so as to be centredbetween same, so that no radial bearing forces can occur at the outputshaft itself. This means that, as compared to simple prior art angledrives, the load on the housing is reduced considerably, so thatmaterial savings could be possible. Furthermore, by providing the ringgearwheels in the form of crown wheels and the output and intermediategearwheels in the form of straight pinions, the assembly procedure issimplified because the pinions can move radially towards the crownwheels without there occurring any change in the type of engagement. Therequirements in respect of the accuracy of the axial position of theoutput gear and of the intermediate gears with reference to axes A₂, A₃and A₄ are thus reduced.

The above-mentioned measures, which lead to the load on the housingbeing reduced, simultaneously cause the shafts and gearwheels to beacoustically uncoupled from the housing. This is an advantageous sideeffect with occurs automatically in the angle drive in accordance withthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Two preferred embodiments of the invention are illustrated in thedrawings and will be described below.

FIG. 1 shows an inventive drive in a section through the input shaft andthe output shaft in a first embodiment.

FIG. 2 shows the drive according to FIG. 1 in a section expendingperpendicularly relative to the input shaft through the output shaft.

FIG. 3 shows an inventive drive in a section through the input shaft andthe output shaft in a second embodiment.

FIG. 4 shows the drive according to FIG. 3 in a section extendingperpendicularly relative to the input shaft through the output shaft.

DETAILED DESCRIPTION OF THE INVENTION

Below, FIGS. 1 and 2 will be described jointly. The housing 11 of anangle drive comprises a flange sleeve 12 with a threaded flange 13having a first axis A₁, by means of which the angle drive can be flangedto a differential drive for example, as a well as a cover 14 positionedopposite the threaded flange 13. At the drive housing 11, there isformed on a housing sleeve 15 whose axis A₂ is aligned radially relativeto the axis A₁ of the flange sleeve 12. An input shaft 16 having an axisA₁ and carrying an input ring gear 19 is floatingly supported by twoball bearings 17, 18 in the drive housing. The input ring gear ispositioned on a seat face 21 of the input shaft 16 and is axiallysupported on a collar 22 to which it is welded. A counter ring gear 20having the same type of toothing and the same size as the input ringgear 19 is positioned symmetrically relative to the latter. The counterring gear 20 is freely rotatably supported on the input shaft 16 via aradial bearing 23 and is supported on the input shaft 16 via an axialbearing 24, a disc 25 and a securing ring 26. The input ring gear 19 andthe counter ring gear 20 are provided in the form of crown wheels. Bothengage an output gearwheel 27 which is formed so as to be integral withan output shaft journal 28. Said output gearwheel 27 is provided in theform of a straight spur gear. The output shaft journal 28 is supportedvia a ball bearing 29 in the sleeve projection 15. The output gearwheel27 engages the input ring gear 19 and the counter ring gear 29, and thisalso applies to two intermediate gearwheels 31, 32 which also compriseaxes A₃, A₄ which are aligned radially relative to the first axis A₁ andwhich are positioned in the same plane as the second axis A₂. Theintermediate gearwheels 31, 32 run via needle bearings 49, 50 on rotaryjournals 33, 34 which are supported in a carrier structure 25 boltedinto the housing 11 by means of bolts 36, 37. A connecting flange 38 isfixed by means of a disc 40 and a bolt to the end of the shaft journal28, with the shaft journal 28 and the connecting flange 38 engaging oneanother by means of a shaft toothing 39. The input shaft 16 is sealed bya seal 42 relative to the threaded flange 13 and sealed by a seal 43relative to the cover 14. Furthermore, the output shaft 28 is sealed bya seal 44 relative to the sleeve projection 15. The input shaft 16 isprovided in the form of a hollow shaft, with a through-shaft 45 passingthrough said input shaft 16. The through-shaft 45 is sealed by a seal 46relative to the input shaft 16. the torque introduced via the inputshaft 16 is completely uniformly distributed via the intermediategearwheels 31, 32 to the two ring gears 19, 20. The tooth forces at thering gears 19, 20 are accommodated in the form of internal forces by theinput shaft 16. The housing 11 remains completely free from axial loadsin the direction of the axis A₁ through the input shaft 16. The ringgears 19, 20 which are floatingly arranged on the input shaft 16 areheld and centered as a result of the symmetric arrangement of thegearwheels 27, 31, 32, so that no radial forces of any worthwhile valuereach the housing 11 from the input shaft 16. The output gearwheel 27 iscentered between the ring gears 19, 20, so that the shaft journal 28 isnot subjected to any bending forces. As a result of the tooth shape(straight-toothed pinions) and the double engagement with the ring gears19, 20, the output gear 27 and the bearing of the output shaft journal28 are not subjected to axial forces either.

FIGS. 3 and 4 will be described jointly below. A housing 51 of an angledrive is bolted to a flange sleeve 52 which is provided with a threadedflange 53 which comprises a first axis A₁ and by means of which theangle drive can be flanged to a differential drive for example, as wellas with a cover 54 arranged opposite the flange 52. At the drive housing51, there is flanged on a housing sleeve 55 whose axis A₂ is alignedradially relative to the axis A₁. The annular drive housing 51, via asingle radial spoke 88, holds a hub 87 which extends coaxially relativeto the axis A₁. An input shaft 56 with an axis A₁ is supported in saidhub 87 by means of a radial bearing 57. On one side of the bearingregion, the input shaft 56 carries an input ring gear 59 which ispositioned on a seat face 61 of the input shaft 56 and is axiallysupported on a collar 62 to which it is welded. On the other side of thebearing region and symmetrically relative to the input ring gear 59,there is positioned a counter ring gear 60 with the same tooth formationand the same size. The counter ring gear 60 is freely rotatablysupported on the input shaft 56 by means of a radial bearing 63 and issupported on the input shaft by means of an axial bearing 64, a disc 65and a securing ring 66. The input ring gear 59 and the counter ring gear60 are provided in the form of crown wheels. Both engage an outputgearwheel 67 which is formed so as to be integral with an output shaftjournal 68. Said output gearwheel 67 is a straight spur gear. The outputshaft journal 68 is supported by a ball bearing 69 in the sleeveprojection 55. The output gearwheel 67 engages the input ring gear 59and the counter ring gear 60, and this also applies to two intermediategearwheels 71, 72 which also comprise axes A₃, A₄ which are alignedradially relative to the first axis A₁ and which are positioned in thesame plane as the second axis A₂. The intermediate gearwheels 71, 72 runon rotary journals 73, 74 which are supported on the radial outside inthe housing 51 and on the radial inside in the hub 83. The rotaryjournals are secured by securing rings 95, 96 and sealed by O-rings 97,98. The intermediate gearwheels 71, 72 are supported on needle bearings89, 90. The input shaft 56 is connected to a plug-in sleeve 99 via ashaft toothing 100. The input shaft 56 with the plug-in sleeve 99 isprovided in the form of a hollow shaft, with a through-shaft 85 passingthrough same. The input shaft is sealed by a seal 83 relative to thecover 54 and the through-shaft 85 is sealed by a seal 86 relative to theinput shaft 56. A connecting flange 78 is fixed by a disc 80 and a bolt81 to the end of the output shaft 68. The shaft journal 68 and theconnecting flange 78 are secured against rotation by a shaft toothing79. Furthermore, the output shaft 68 is sealed by a seal 84 relative tothe sleeve 55. The torque introduced via the input shaft 56 iscompletely uniformly distributed via the intermediate gearwheels 71, 72to the two ring gears 59, 60. The tooth forces at the ring gears 59, 60are accommodated in the form of internal forces within the input shaft16 and hold the annular housing 51 completely free from axial loads inthe direction of the axis A₁. Furthermore, the axially floatinglyarranged input shaft 56 is held and centered as a result of thesymmetric arrangement of the gearwheels 67, 71, 72, so that no radialforces of any worthwhile values reach the housing 51 from the inputshaft 56. The output gearwheel 67 is centered between the ring gears 59,60, so that the shaft journal 68 is not subjected to any bending forces.As a result of the tooth shape (straight-toothed pinion) and the doubleengagement with the ring gears 59, 60, the output gear 67 and thebearing 69 of the output shaft journal 28 are not subjected to axialforces either.

List of Reference Numbers

-   11, 51 housing-   12, 52 flange sleeve-   13, 53 flange-   14, 54 cover-   15, 55 sleeve-   16, 56 input shaft-   17, 57 bearing-   18 bearing-   19, 59 input ring gear-   20, 60 counter ring gear-   21, 61 seat-   22, 62 collar-   23, 63 radial bearing-   24, 64 axial bearing-   25, 65 disc-   26, 66 securing ring-   27, 67 output gearwheel-   28, 68 shaft journal-   29, 69 bearing-   30, 70-   31, 71 intermediate gearwheel-   32, 72 intermediate gearwheel-   33, 73 journal-   34, 74 journal-   35 journal carrier-   38, 78 connecting flange-   39, 79 toothing-   40, 80 disc-   41, 81 bolt-   42 seal-   43, 83 seal-   44, 84 seal-   45, 85 through-shaft-   46, 86 seal-   87 hub-   88 spoke-   49, 89 needle bearing-   50, 90 needle bearing-   91 bore-   92 bore-   93 countersunk region-   94 countersunk region-   95 securing ring-   96 securing ring-   97 O-ring-   98 O-ring-   99 plug-in sleeve-   100 toothing-   101 outer ring

1. An angle drive comprising: a housing; a hollow input shaft which issupported in the housing, and which carries an input ring gear and ispositioned on a first axis (A₁); an output shaft which is supported inthe housing, and which carries an output gearwheel and is positioned ona second axis (A₂) which intersects the first axis (A₁) at a rightangle; a counter ring gear which is supported on the input shaft by aradial bearing and an axial bearing respectively, and, which ispositioned on the first axis (A₁) and which, with reference to thesecond axis (A₂), is arranged and designed symmetrically relative to theinput ring gear; and two intermediate gearwheels each supported in thehousing and arranged on an axis (A₃, A₄) positioned radially relative tothe first axis (A₁) and in the same plane as, and forming identicalpitch angles with, the second axis (A₂), each intermediate gearwheelhaving the same type of toothing as the output gearwheel; wherein thecounter ring gear is supported so as to be independently rotatablerelative to the input ring gear, and wherein the input ring gear and thecounter ring gear are crown wheels which, via their respective teeth,simultaneously engage the output gearwheel and each intermediategearwheel, the output gearwheel and the intermediate gearwheels beingspur gears with straight or helical toothing; wherein the housingcomprises a spoke supporting a hub extending coaxially with the firstaxis (A₁) and wherein the input shaft is supported by the hub; andwherein the intermediate gearwheels each run on respective rotaryjournals supported at one end by the housing and at another end by thehub.
 2. An angle drive comprising: a housing; a hollow input shaft whichis supported in the housing, and which carries an input ring gear and ispositioned on a first axis (A₁); an output shaft which is supported inthe housing, and which carries an output gearwheel and is positioned ona second axis (A₂) which intersects the first axis (A₁) at a rightangle; a counter ring gear which is supported on the input shaft by aradial bearing and an axial bearing respectively, and, which ispositioned on the first axis (A₁) and which, with reference to thesecond axis (A₂), is arranged and designed symmetrically relative to theinput ring gear; and two intermediate gearwheels each supported in thehousing and arranged on an axis (A₃, A₄) positioned radially relative tothe first axis (A₁) and in the same plane as, and forming identicalpitch angles with, the second axis (A₂), each intermediate gearwheelhaving the same type of toothing as the output gearwheel; wherein thecounter ring gear is supported so as to be independently rotatablerelative to the input ring gear, and wherein the input ring gear and thecounter ring gear are crown wheels which via their respective teeth,simultaneously engage the output gearwheel and each intermediategearwheel, the output gearwheel and the intermediate gearwheels beingspur gears with straight or helical toothing; and wherein the housingcomprises, on its inside, a carrier structure and wherein theintermediate gearwheels each run on respective rotary journals supportedby the carrier structure.